1. Field of the Invention
This invention relates to an interconnector for installation in an opening in a partition or wall to provide at least one electrical connection through the partition or wall. The invention also relates to a method of making such an interconnector. The invention is primarily concerned with an interconnector for use in a nuclear plant, though the interconnector is suited for use in other structures.
2. Description of the Prior Art
The reactor core of a nuclear plant is housed in a pressure-tight containment and many electrical connections have to pass through the wall of the containment so that the core can be monitored and controlled. Usually interconnectors are sealed in openings in a partition plate which is then installed in an opening in the primary containment wall. Each interconnector, which is often referred to as a feedthrough module, includes a plurality of spaced electrical conductors which are insulated from one another and which extend through the interconnector. In some interconnectors the conductors are spaced and insulated by means of epoxy resin seals but in certain applications glass sealing members are required.
The conductors serve to interconnect respective electrical circuits either side of the partition plate (otherwise known as a header plate) and this is effected by mating connectors at the ends of cables on either side of the partition plate with the connectors formed by the respective ends of the feedthrough module.
A header plate with sealed feedthrough modules is termed an electric penetration assembly. Such an assembly has to fulfil two main functions; firstly to maintain the pressure-tight integrity of the primary containment, and secondly to ensure that there is no break in the electrical circuity.
Since cost of maintenance is high in a nuclear plant, and since safety is a crucial factor, it is desirable to be able to verify that an effective seal obtains at each feedthrough module while the plant is in operation. To this end designs for electric penetration assemblies have been adopted which provide for detecting any failure in the seals. In such designs, two seals are provided in series for each interconnector with a space therebetween. This can be achieved either by placing two header plates in series in an opening in the containment wall with each interconnector passing through corresponding openings in the two header plates and sealed against them, or using a single header plate and sealing the interconnector at two spaced locations against the opening through the header plate. In either case, the pressure in the space between the seals is established at a value intermediate that of the interior (high pressure) and the exterior (atmospheric pressure) and then monitored. A drop in pressure indicates a leak to the exterior, while a rise in pressure indicates a leak from the interior.